syzbot


KCSAN: data-race in dev_get_tstats64 / udp_tunnel6_xmit_skb (3)

Status: auto-closed as invalid on 2022/03/07 16:56
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 302d, last: 299d
similar bugs (3):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in dev_get_tstats64 / udp_tunnel6_xmit_skb (4) 8 172d 259d 0/24 auto-closed as invalid on 2022/07/12 12:23
upstream KCSAN: data-race in dev_get_tstats64 / udp_tunnel6_xmit_skb 6 625d 708d 0/24 auto-closed as invalid on 2021/04/15 10:49
upstream KCSAN: data-race in dev_get_tstats64 / udp_tunnel6_xmit_skb (2) 3 343d 373d 0/24 auto-closed as invalid on 2022/01/22 10:01

Sample crash report:
==================================================================
BUG: KCSAN: data-race in dev_get_tstats64 / udp_tunnel6_xmit_skb

write to 0xffffe8ffffc43d70 of 8 bytes by task 43 on cpu 0:
 iptunnel_xmit_stats include/net/ip_tunnels.h:453 [inline]
 ip6tunnel_xmit include/net/ip6_tunnel.h:166 [inline]
 udp_tunnel6_xmit_skb+0x3ce/0x4d0 net/ipv6/ip6_udp_tunnel.c:109
 send6+0x2f1/0x3b0 drivers/net/wireguard/socket.c:152
 wg_socket_send_skb_to_peer+0xbb/0x130 drivers/net/wireguard/socket.c:177
 wg_socket_send_buffer_to_peer+0xf7/0x120 drivers/net/wireguard/socket.c:199
 wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:40 [inline]
 wg_packet_handshake_send_worker+0x109/0x150 drivers/net/wireguard/send.c:51
 process_one_work+0x3f6/0x960 kernel/workqueue.c:2307
 worker_thread+0x616/0xa70 kernel/workqueue.c:2454
 kthread+0x1bf/0x1e0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30

read to 0xffffe8ffffc43d70 of 8 bytes by task 1816 on cpu 1:
 dev_fetch_sw_netstats net/core/dev.c:10058 [inline]
 dev_get_tstats64+0x13a/0x1e0 net/core/dev.c:10081
 dev_get_stats+0x65/0x180 net/core/dev.c:10023
 rtnl_fill_stats+0x45/0x320 net/core/rtnetlink.c:1203
 rtnl_fill_ifinfo+0xf16/0x25b0 net/core/rtnetlink.c:1776
 rtmsg_ifinfo_build_skb+0xa8/0x130 net/core/rtnetlink.c:3833
 rtmsg_ifinfo_event net/core/rtnetlink.c:3865 [inline]
 rtmsg_ifinfo+0x58/0xc0 net/core/rtnetlink.c:3874
 __dev_notify_flags+0x63/0x3b0 net/core/dev.c:8173
 dev_change_flags+0xa2/0xc0 net/core/dev.c:8215
 do_setlink+0x820/0x2500 net/core/rtnetlink.c:2729
 __rtnl_newlink net/core/rtnetlink.c:3412 [inline]
 rtnl_newlink+0xfad/0x13b0 net/core/rtnetlink.c:3527
 rtnetlink_rcv_msg+0x745/0x7e0 net/core/rtnetlink.c:5592
 netlink_rcv_skb+0x14e/0x250 net/netlink/af_netlink.c:2494
 rtnetlink_rcv+0x18/0x20 net/core/rtnetlink.c:5610
 netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline]
 netlink_unicast+0x602/0x6d0 net/netlink/af_netlink.c:1343
 netlink_sendmsg+0x728/0x850 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:705 [inline]
 sock_sendmsg net/socket.c:725 [inline]
 __sys_sendto+0x21e/0x2c0 net/socket.c:2040
 __do_sys_sendto net/socket.c:2052 [inline]
 __se_sys_sendto net/socket.c:2048 [inline]
 __x64_sys_sendto+0x74/0x90 net/socket.c:2048
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000000001 -> 0x0000000000000002

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 1816 Comm: syz-executor.0 Not tainted 5.17.0-rc2-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (2):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2022/01/31 16:55 upstream 26291c54e111 a491ad2d .config log report info KCSAN: data-race in dev_get_tstats64 / udp_tunnel6_xmit_skb
ci2-upstream-kcsan-gce 2022/01/28 00:44 upstream 626b2dda7651 64a8e201 .config log report info KCSAN: data-race in dev_get_tstats64 / udp_tunnel6_xmit_skb
* Struck through repros no longer work on HEAD.